Semiconductor device socket

ABSTRACT

A semiconductor device socket preventing adhesion of foreign material to mounting surfaces of external leads of a semiconductor device. In the semiconductor device socket, a positioning base supports a shoulder of each of external leads extending from the semiconductor device without contacting the base and the contact portion of each of the movable contact terminals makes electrical contact with the shoulder of the corresponding external lead. The movable contact terminals are disposed opposite to the external leads outside of the positioning base and are opened and closed as a movable cover is moved relative to the base.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device socket forconnecting an external circuit to external leads of a surface packagetype semiconductor device in order to test the device.

2. Description of the Related Art

FIGS. 13 and 14 are sectional views illustrating the basic structure ofa conventional semiconductor device socket. FIG. 13 illustrates a statewhere movable contact terminals of the socket are open, and FIG. 14illustrates a state where the movable contact terminals are closed. FIG.15 is a partial perspective view illustrating only a portion near asemiconductor device which is mounted on a socket. In FIGS. 13, 14 and15, reference numeral 1 denotes a surface package type semiconductordevice (referred to as IC hereinafter); reference numeral 2, a pluralityof gull wing-like external leads which extend from both sides of the IC1, as shown in FIG. 10; and reference numeral 3, a package portion. Eachof the external leads 2 has a shoulder 4, a flat end 5, a mountingsurface 6 on the rear side of the end 5, and an upper surface 7 on thefront side thereof. The mounting surface 6 contacts an electrode (notshown) on a circuit substrate when the IC 1 is actually mounted on thecircuit substrate.

Reference numeral 50 denotes a semiconductor device socket comprising abody 20 for mounting the IC 1 thereon, and a movable cover 40 which isprovided on the body 20 so as to be vertically movable.

The body 20 has a positioning base 21 for supporting the package portion3 of the IC 1 and positioning the IC 1, terminal guides 22 for guidingthe ends 5 of the external leads 2 of the IC 1 and aligning the movablecontact terminals 30 described below, and a lead end supporting surface23 for supporting the mounting surface 6 of each of the external leads2. Reference numeral 30 denotes the movable contact terminal provided incorrespondence with each of the external leads 2. The movable contactterminals 30 are provided in a row on both sides of the positioning base21 outside the positioning base 21 in correspondence with the respectiveexternal leads 2, and the terminal guides 22 are provided between therespective movable contact terminals 30. In a socket for a QFP (QuadFlat Package) type semiconductor, the movable contact terminals 30 areprovided on each of the four sides. Each of the movable contactterminals 30 has a lever portion 31, a contact portion 32, and aterminal portion 33 for electrical connection with an external circuit(not shown).

The movable cover 40 has an opening 41 for getting the IC 1 in and outof the socket 50, the IC 1 being mounted on the positioning base 21through the opening 41 while the external leads 2 are respectivelyguided by the terminal guides 22. The movable cover 40 also has anengagement portion 42 on the rear side thereof, which has an arcuatesurface 43 contacting the lever portion 31 of each of the movablecontact terminals 30 to open and close each of the movable contactterminals 30 as the movable cover 40 is vertically moved.

The operation of the conventional semiconductor device socket isdescribed below.

When the movable cover 40 of the socket 50 is downwardly moved to engagethe body 20, as shown in FIG. 13, the lever portion 31 of each of themovable contact terminals 30 is forced open by the arcuate surface 43 onthe rear side of the movable cover 40, and the contact portion 32 isupwardly retracted along a circular arc. In this state, the IC 1 ismounted on the positioning base 21 of the body 20, as shown in FIG. 13.

When the pressure pushing down the movable cover 40 is removed, each ofthe movable contact terminals 30 made of an elastic metal material suchas BeCu or the like is returned to the closed state by its own elasticforce, and the contact portion 32 consequently pushes the upper surface7 at the end 5 of the corresponding external lead 2 of the IC 1. At thesame time, the movable cover 40 is pushed up by the elastic force ofeach of the movable contact terminals 30 and separated from the body 20.In this state, the contact portion 32 of each of the movable contactterminals 30 pushes the upper surface 7 at the end 5 of thecorresponding external lead. 2 supported on the lead end supportingsurface 23 of the body 20, as described above, thereby achievingelectrical connection between the movable leads 2 and the respectivecorresponding external leads 2. The above operation causes the IC 1 tobe mounted on and separated from the socket 50 in order to perform testssuch as the electrical characteristic test and burn-in screen test ofthe IC.

In the conventional semiconductor device socket configured as describedabove, the ends of the external leads of the IC respectivelyelectrically contact the movable contact terminals on the socket side.However, since a solder coating (not shown) is previously placed on theend of each of the external leads when the IC is mounted on the circuitsubstrate, and since the lead end contacts directly an electrode on thecircuit substrate when the IC is mounted on the circuit substrate, andis thus required to be planar, it is undesirable that the ends of theexternal leads make electrical contact. This is due to the followingproblems:

(1) If the lead ends make electrical contact, since the contactterminals on the socket side are pressed, the solder coating isseparated.

In addition, when an IC having resin burrs which adhere to portionsbetween the respective external leads is mounted on the socket in orderto perform function tests in the course of the production of the IC orimmediately after the production, various foreign materials A such asthe mold burrs separated from the portions between the external leads ofthe IC package portion, fiber flocks of the clothing of the workers etc.in the room remain and are deposited on the body including the lead endsupporting surface 23 of the socket, as shown in FIG. 15. If themounting surfaces at the ends of the external leads of the IC arepressed on the surface of the body of the socket in this state, theforeign materials A sometimes adhere to the mounting surfaces of theexternal leads. This causes the following problems:

(2) When a test for electrical connection of the mounting surfaces ofthe external leads is then performed, or when the IC is actually mountedon the circuit substrate, the foreign materials which adhere to themounting surfaces cause poor electrical contact; and

(3) Since a force is applied in the state where the foreign materialsadhere, the lead ends are deformed, as shown by portion B in FIG. 15,thereby causing a defective product.

SUMMARY OF THE INVENTION

The present invention has been achieved for solving the above problems,and an object of the present invention is to provide a semiconductordevice socket which can prevent the adhesion of foreign materials to themounting surfaces of external leads of IC and the deformation of thelead ends respectively including the mounting surfaces.

In order to achieve the object, in accordance with a first embodiment ofthe present invention, a semiconductor device socket for connecting anexternal circuit to the external leads of a semiconductor device inorder to test the device, comprises a body and a movable cover. The bodysupports the mounting surface at the end of each of the external leadsof the semiconductor device and comprises movable contact terminalsprovided opposite to the respective external leads of the semiconductordevice. The movable cover is provided on the body so as to be verticallymovable so that the semiconductor device can be mounted when the movablecover is downwardly moved to connect with the body, and the movablecontact terminals respectively press the shoulders or inclined portionsof the external leads of the semiconductor device when the movable coveris upwardly moved to be separated from the body.

In accordance with a second embodiment of the present invention, eachcontact portion of the movable contact terminals of the semiconductordevice socket in accordance with the first embodiment has a projectionhaving a wiping effect, cutting off thin burrs remaining on a shoulderof each of the external leads when contacting the shoulder.

In accordance with a third embodiment of the present invention, asemiconductor device socket for connecting an external circuit toexternal leads of a semiconductor device in order to test the device,comprises a body and a movable cover. The body supports thesemiconductor device and comprises a lead end supporting surface forsupporting the mounting surfaces at the ends of the external leads ofthe semiconductor device, and movable contact terminals disposedopposite to the external leads of the semiconductor device. The movablecover is provided on the body so as to be vertically movable so that thesemiconductor device can be mounted when the movable cover is moved tocombine with the body, and the movable contact terminals respectivelypress the face sides of the mounting surfaces of the external leads ofthe semiconductor device when the movable cover is moved to be separatedfrom the body.

In accordance with a fourth embodiment of the present invention, asemiconductor device socket for connecting an external circuit toexternal leads of a semiconductor device in order to test thesemiconductor device, comprises a body and a movable cover. The bodysupports the semiconductor device and comprises a lead end supportingsurface for supporting mounting surfaces of external leads of thesemiconductor device, and movable contact terminals disposed opposite tothe external leads of the semiconductor device. The movable cover isprovided on the body so as to be vertically movable so that thesemiconductor device can be mounted when the movable cover is moved tocombine with the body, and the movable contact terminals respectivelypress the face sides of the mounting surfaces of the external leads ofthe semiconductor device when the movable cover is moved to be separatedfrom the body. The lead end supporting surface of the body respectivelyhas resilient movable projecting members which project therefrom andwhich are provided on portions corresponding to the mounting surfaces ofthe external leads. The movable projecting members are pushed down to aposition on or below the level of the lead end supporting surface levelwhen pressed by the movable contact terminals.

In accordance with a fifth embodiment of the present invention, asemiconductor device socket for connecting an external circuit toexternal leads of a semiconductor device in order to test thesemiconductor device, comprises a body and a movable cover. The bodycomprises an IC supporting surface for supporting the semiconductordevice, and movable contact terminals disposed opposite to externalleads of the semiconductor device. The movable cover is provided on thebody so as to be vertically movable so that the semiconductor device canbe mounted when the movable cover is moved to combine with the body, andthe movable contact terminals contact the face sides of the mountingsurfaces of the external leads of the semiconductor device when themovable cover is moved to be separated from the body. The IC supportingsurface of the body is provided with projecting positioning guides forpositioning the semiconductor device while contacting both sides of apackage portion.

In accordance with a sixth embodiment of the present invention, asemiconductor device socket for connecting an external circuit toexternal leads of a semiconductor device in order to test thesemiconductor device at a different temperature, comprises a body forsupporting the semiconductor device in the state where the mountingsurfaces at the ends of the external leads float. The body comprisesmovable contact terminals provided opposite to the external leads of thesemiconductor device. Each of the movable contact terminals is made of ashape memory alloy so as to memorize the shape in the state when themovable contact terminals press the external leads, and to return to thememorized state at a test temperature.

In the semiconductor device socket in accordance with the firstembodiment, the electrical contact between the external leads of thesemiconductor device and the movable contact terminals on the connectorside is achieved by the shoulders or the inclined portions of theexternal leads, and when the semiconductor device is mounted on thesocket, the semiconductor device is supported by the sides of theshoulders of the external leads on the rear side thereof, and themounting surfaces of the external leads float, i.e., do not contact thesocket. It is thus possible to prevent adhesion of foreign materials tothe mounting surfaces. In addition, the ends of the external leads donot make electrical connection, thereby preventing the lead ends frombeing deformed by the pressure acting thereon at the time of the test.

In the semiconductor device socket in accordance with the secondembodiment, since, in the socket of the first embodiment, the thin burrsproduced in the formation of the package portion remain on the shouldersof the external leads which contact the contact portions of the movablecontact terminals, the contact portion of each of the movable contactterminals includes a projection having sharp form so as to cut off thethin burrs when contacting the corresponding shoulder, thereby reliablyobtaining good electrical contact.

In the semiconductor device socket in accordance with the thirdembodiment, although electrical connection between the external leadsand the movable contact terminals is achieved by the ends of theexternal leads, the lead end supporting surface of the socket body forsupporting the mounting surfaces of the external leads is formed in ashape or made of a material which prevents deposition and retention offoreign materials by including irregularities or bonding with aconductive material so as to prevent the generation of staticelectricity. It is thus possible to decrease the adhesion of foreignmaterials to the mounting surfaces of the external leads.

In the semiconductor device socket in accordance with the fourthembodiment, the lead end supporting surface of the socket body isprovided with movable projecting members each of which has a resiliencelower than that of the movable contact terminals, which respectivelyupwardly project from the lead end supporting surface when not beingpressed by the contact portions of the movable contact terminals, andwhich are respectively provided in correspondence with the externalleads so that foreign materials hardly deposit and remain on the movableprojecting members in contact with the mounting surfaces of the externalleads. It is thus possible to decrease the adhesion of foreign materialsto the mounting surfaces of the external leads.

In the semiconductor device socket in accordance with the fifthembodiment, the IC positioning means comprises projecting positioningguides, each of which has, for example, a conical or truncated conicalshape, which makes point contact with the sides of the package portion,and which are provided on the IC supporting surface of the socket body,so that the deposition and retention of foreign materials can bedecreased, and the foreign materials can easily be cleaned off. It isthus possible to decrease the adhesion of the foreign materials to themounting surfaces of the external leads.

In the semiconductor device socket for testing at a differenttemperature in accordance with the sixth embodiment, each of the movablecontact terminals is made of a shape memory alloy which memorizes ashape in the state where the movable contact terminal contacts thecorresponding external lead, and which returns to the memorized shape ata test temperature so as to automatically have a shape for pressing thecorresponding external lead when being placed in an environment at thetest temperature. This makes it unnecessary to provide a movable coverfor opening and closing the movable contact terminals on the socket. Inaddition, the movable contact terminals are opened by a cam portion orthe like which is formed on a conveyance tool provided separately fromthe socket so as to convey, for example, the IC, with vacuum tweezers tothe socket.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view illustrating a semiconductor device socket inaccordance with a first embodiment of the present invention;

FIG. 2 a partial sectional view illustrating the relation between thesocket and the shape of an external lead of the semiconductor deviceshown in FIG. 1;

FIG. 3 is a sectional view illustrating a modified embodiment of thesemiconductor device socket in accordance with the first embodiment ofthe present invention;

FIGS. 4A to 4D are partial perspective views illustrating examples ofmovable contact terminals of a semiconductor device socket in accordancewith a second embodiment of the present invention;

FIG. 5 is a partial perspective view illustrating another example of themovable contact terminals of the semiconductor device socket;

FIG. 6 is a partial perspective view illustrating a semiconductor devicesocket in accordance with a third embodiment of the present invention;

FIG. 7 is a partial perspective view illustrating a modified embodimentof the semiconductor device socket in accordance with the thirdembodiment of the present invention;

FIG. 8 is a partial perspective view with a sectional portionillustrating a semiconductor device socket in accordance with a fourthembodiment of the present invention in the state where movable contactterminals are open;

FIG. 9 is a partial perspective view with a sectional portionillustrating a semiconductor device socket in accordance with the fourthembodiment of the present invention in the state where movable contactterminals are closed;

FIG. 10 is a partial perspective view illustrating a semiconductordevice socket in accordance with a fifth embodiment of the presentinvention;

FIG. 11 is a sectional view illustrating a semiconductor device socketin accordance with a sixth embodiment of the present invention in thestate where movable contact terminals are open;

FIG. 12 is a sectional view illustrating a semiconductor device socketin accordance with the sixth embodiment of the present invention in thestate where the movable contact terminals are closed;

FIG. 13 is a sectional view of a conventional semiconductor devicesocket in the state where movable contact terminals are open;

FIG. 14 is a sectional view of a conventional semiconductor devicesocket in the state where movable contact terminals are closed; and

FIG. 15 is a partial perspective view illustrating the state where asemiconductor device is mounted on a conventional semiconductor devicesocket.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are described below with referenceto the drawings.

Embodiment 1

FIG. 1 is a sectional view illustrating a semiconductor device socket inaccordance with a first embodiment of the present invention. In FIG. 1,the same portions as those of a conventional socket are denoted by thesame reference numerals. The semiconductor device socket 50a comprisesthe body 20a on which the IC 1 is mounted, and the movable cover 40provided on the body 20a so as to be vertically movable, the body 20aand movable cover 40 being integrally provided. In this embodiment, thepositioning base 21a formed on the body 20 positions and supports the IC1 so as to support the shoulder 4 of each of the external leads 2 of theIC 1 while the mounting surface 6 at the end 5 of each of the externalleads 2 floats without contacting any portion. The package portion 3 ofthe IC 1 also floats. On the other hand, the contact portion 32a of eachof the resilient movable contact terminals 30a is extended so as tocontact the shoulder 4 of each of the external leads 2 supported by thepositioning base 21a. It is thus preferable that each of the terminalguides 22a be wider than a conventional one according to demand, asshown in FIG. 1. It is also preferable that movable terminal guides 22awhich move in accordance with the movement of the movable contactterminals 30a be provided. FIG. 1 shows the state where the IC 1 ismounted on the socket 50, and the contact portions of the movablecontact terminals 30a respectively contact and press against theshoulders 4 of the external leads 2.

The operation of the embodiment is described below. The basic structureand operation for mounting or separating the IC 1 on or from the socket50a are as described above with reference to the conventional socket. Inthis embodiment, after the IC 1 is positioned on the positioning base21a provided on the body 20a of the socket 50, when the movable cover 40is returned to the state (separation position) shown in FIG. 1, thecontact portions 32a of the movable contact terminals 30a respectivelycontact the shoulders 4 of the external leads 2 of the IC 1 and pressagainst them. In this state, since the mounting surfaces 6 at the ends 5of the external leads 2 float without contacting the socket 50a, noforeign materials (mold scraps of the IC package, fiber flocks, etc)adhere to the mounting surfaces.

It is thus possible to prevent separation of the solder (not shown)coating from the lead ends 5, and poor contact caused by the adhesion ofthe foreign materials to the mounting surfaces 6. In addition, since thelead ends 5 do not make electrical contact, it is also possible toprevent the deformation of the lead ends 5 which are required to beplanar. There is only a little possibility of deformation of theexternal leads 2 because the contact portions 32a of the movable contactterminals 30a are respectively pressed by the strong shoulders 4 of theexternal leads 2. Further, since the shoulders 4 of the external leads2, i.e., the roots of the external leads 2, contact the contact portions32a of the movable contact terminals 30a, the socket can be used for ICshaving external leads of different forms, as shown in FIG. 2, if thesize of the package portion 3 and the pitch of the external leads 2 arethe same.

FIG. 3 is a sectional view illustrating a modified version of asemiconductor device socket in accordance with the first embodiment ofthe present invention. Although FIG. 1 shows the embodiment in which theshoulder 4 of each of the external leads 2 of the IC 1 makes electricalcontact, FIG. 3 shows the embodiment in which the inclined portion ofeach of the external leads makes electrical contact. In this embodiment,the contact portion 32b of each of the movable contact terminals 30a isformed so as to contact the inclined portion 8 of each of the externalleads 2 and press against them. The positioning base 21b of the body 20ahas a shape having a lead end supporting surface 24 parallel with theinclined portions 8 of the external leads 2 in order to support theinclined portions of the external leads 2 when the inclined portions 8are pressed by the movable contact.

This structure prevents the mounting surfaces 6 of the external leads 2from contacting the socket 50a and thus prevents the poor contact anddeformation which are caused by separation of the solder from the leadends 5 and adhesion of foreign materials thereto, as in the arrangementshown in FIG. 1.

Embodiment 2

FIGS. 4A to 4D are partial perspective views illustrating examples ofthe contact portions of movable contact terminals of a semiconductordevice socket in accordance with a second embodiment. In each of theabove embodiments, the shoulders of the external leads of the IC makeelectrical contact with the contact terminals on the socket side.However, since the thin burrs 3a (refer to FIG. 4), which are producedwhen the package portion 3 is formed by molding, remain on the shoulders4 at the roots of the external leads 2, there is the possibility thatgood electrical contact between the external leads and the contactterminals cannot be obtained due to the thin burrs 3a of an insulatingresin.

In this embodiment, the contact portion 320 of a movable contactterminal 300 has projections 320a, as shown in each of FIGS. 4A to 4D.In each of the drawings, character C denotes the wiping marks producedon the shoulder 4 of each of the external leads 2 by the sharp formprojections 320a of the contact portion 320. FIG. 4A shows one linemark, FIG. 4B shows three line marks, FIG. 4C shows three lateral jaggedmarks, and FIG. 4D shows wiping marks on both sides of the shoulder 4.In this way, the contact portion 320 of each of the movable contactterminals 300 has a sharp end projection so as to have the wiping effectof cutting off the thin burrs 3a and reliably obtain the desiredelectrical connection between the external leads 2 and the movablecontact terminals 300. The shape of the projection 320a of the contactportions 320 is not limited to the shapes shown in FIGS. 4A to 4D.

FIG. 5 is a partial perspective view illustrating another example of themovable contact terminals of the semiconductor device socket inaccordance with the first and second embodiments of the presentinvention. In this embodiment, each of the movable contact terminals isa helical spring type contact terminal. As shown in FIG. 5, helicalspring type contact terminals 35 are provided on a shaft 36 whichextends parallel to a row of the external leads 2 of the IC 1, incorrespondence with the respective external leads 2, so as torespectively contact the shoulders 4 of the corresponding external leads2 by their resilience upon operation of a cam 37 extending parallel tothe shaft 36. The contact terminals 35 also respectively press theshoulders 4 to produce good contact pressure for electrical connection.The cam 37 is rotated around a cam shaft 37a by moving a lever 38. Thelever 38 is moved by, for example, operation of the movable cover 40. Ina socket without the movable cover, as in Embodiment 6 shown in FIGS. 11and 12 described below, the lever 38 is moved by operation of aconveying tool 100 for conveying the IC 1 with vacuum tweezers, which isshown in FIG. 11.

The springiness, i.e., the resilience, of each of the helical springtype contact terminals 35 can be adjusted by changing the number ofturns of the spring. The resilience of the helical spring type contactterminals 35 can easily be changed, as compared with the contactterminals of the above embodiments, which are formed by punching ametallic plate. The resilience can also be maintained for a long period.

Embodiment 3

FIG. 6 is a partial perspective view illustrating a semiconductor devicesocket in accordance with a third embodiment of the present invention.In this embodiment, when the contact portions of the contact terminalsare respectively pressed by the ends of the external leads of a IC tomake electrical contact therebetween, as in the prior art shown in FIGS.13 and 14, foreign materials hardly deposit or remain on the socketbody. In this embodiment, each of lead end supporting surfaces 60 forrespectively supporting the mounting surfaces of the external leads 2 onthe outside of the positioning base 21 of the socket body 20a is formedso that a portion for supporting the mounting surface of each of theexternal leads 2 is a convex portion 61 having a minimum necessary area,i.e., all portions which do not contact the mounting surfaces arerecessed portions 62. As a result, foreign materials hardly deposit andremain on the convex portions 61. Even if the ends 5 of the externalleads 2 are supported by the lead end supporting surface 60 of thesocket body 20a in contact therewith, it is thus possible to decreasethe adhesion of foreign materials and decrease the occurrence of poorcontact, which is caused by adhesion of foreign materials, anddeformation of the ends 5 of the external leads 2.

FIG. 7 is a partial perspective view illustrating a modified version ofthe semiconductor device socket in accordance with the third embodimentof the present invention. In this embodiment, a conductive metallicmaterial 63 of Au, Ag, Al, Cu, Cu alloy, W, Ti, Ni or Ni alloy isattached to portions of the lead end supporting surface 60 forsupporting the mounting surfaces 6 of the external leads on the outsideof the positioning base 21 of the socket body 20a. This can preventcharging with static electricity which causes adhesion of foreignmaterials, and can thus decrease the adhesion of foreign materials tothe mounting surfaces 6 of the external leads 2 and decrease theoccurrence of poor contact and deformation of the lead ends.

The conductive material 63 may be provided on each of the convexportions 61 of the lead end supporting surface 60 having irregularitiesshown in FIG. 6 so that the adhesion of foreign materials to themounting surfaces 6 of the external leads 2 can further be decreased.

Embodiment 4

FIGS. 8 and 9 are partial perspective views with sectional portionsrespectively illustrating a semiconductor device socket in accordancewith a fourth embodiment of the present invention. In this embodiment, amovable projecting member 70 having lower elasticity than that of themovable contact terminals 30 is provided on each of the portions of thelead end supporting surface 60, which respectively contact the mountingsurfaces 6 of the external leads so as to support the mounting surfaces6 of the external leads 2 of the IC 1. In the state where the IC 1 isnot mounted on the socket, as shown in FIG. 8, each of the movableprojecting members 70 for contacting the mounting surfaces 6 of theexternal leads 2 thus upwardly projects from the lead end supportingsurface 60 through corresponding hole 64. The foreign materials thushardly deposit on the movable projecting members 70, as compared withother portions of the lead end supporting surface 60, thereby decreasingthe adhesion of the foreign materials to the mounting surfaces 6 of theexternal leads 2. In the state where the IC 1 is mounted on the socket,as shown in FIG. 9, since the pressure of the movable contact terminals30 is higher than the elasticity of the movable projecting members 70,the movable projecting members 70 are pushed down to the same height asthat of the lead supporting surface 60.

As an embodiment of the movable projecting members 70, spring mechanisms70 having lower elasticity than that of the movable contact terminals 30may be contained in a portion below the lead end supporting surface 60,and the ends of the spring mechanisms 70 are projected as the movableprojecting members from the holes formed in the supporting surface 60.

The movable projecting members 70 must be projected from the supportingsurface 60 to a height higher than that of the deposit of foreignmaterials on the supporting surface 60 in the state where the IC is notmounted. The end of each of the movable projecting members 70 ispreferably small and is rounded for preventing deposition of the foreignmaterials.

In this embodiment, not only the pressure caused by the elasticity ofthe movable contact terminals 30 but also the pressure of the movableprojecting members 70 which is caused by the spring mechanisms, areapplied to the upper sides 7 of the mounting surfaces 6 of the externalleads, thereby producing a strong contact force between the upper sides7 of the external leads 2 and the contact portions 32 of the movablecontact terminals 30, and better electrical contact therebetween.

Embodiment 5

FIG. 10 is a partial perspective view illustrating a semiconductordevice socket in accordance with a fifth embodiment of the presentinvention. In this embodiment, four projecting positioning guides 81 areprovided as positioning guides for precisely positioning the IC 1 on theIC supporting surface 80 of the socket body 20a for supporting thepackage portion 3 of the IC 1 and the mounting surfaces of the externalleads 2 so that the four projecting positioning guides 81 contact thefour corners of the package portion 3. Each of the projectingpositioning guides 81 has, for example, a conical or truncated conicalform. A V-shaped groove 82 for guiding the foreign materials depositedon the IC supporting surface 80 is also provided in the IC supportingsurface 80 below the package portion 3 of the IC 1.

In a conventional structure, since the positioning base comprises awall-like projecting portion (positioning base 21) having substantiallythe same length as that of one side of the IC 1, as shown in FIG. 15,foreign materials easily deposit and remain on the body 20. In addition,since the wall-like projecting portion extends over substantially thesame length as that of one side of the IC 1, much labor is required forcleaning off the foreign materials. In this embodiment, therefore, thepositioning guides are conical or truncated conical projectingpositioning guides 81 which are provided in contact with the fourcorners of the package portion 3 of the IC 1 so as to make point contactwith the package portion 3 of the IC 1 without interfering with theexternal leads 2. The package portion 3 of the IC 1 is thus guided bymembers having a minimum length. In addition, since the V-shaped groove82 is formed below the package portion 3 of the IC 1, it is possible todecrease the deposition and retention of the foreign materials on thesurface of the IC supporting surface 80 and easily clean off thedeposited foreign materials, thereby decreasing the adhesion of theforeign materials to the mounting surfaces 6 of the external leads 2.The number and position of the projecting positioning guides 81 are notlimited to those described above.

Embodiment 6

FIGS. 11 and 12 are sectional views illustrating a semiconductor devicesocket in accordance with a sixth embodiment of the present invention.FIG. 11 shows the state where the movable contact terminals of thesocket are open, and FIG. 12 shows the state where the movable contactterminals are closed. This embodiment is applied to a socket on which aIC is mounted for testing, for example, in a high-temperatureenvironment. Each of the movable contact terminals of the socket ofEmbodiment 9 is made of a shape memory alloy so that the movable coverof the socket is made unnecessary. As shown in FIGS. 11 and 12, asemiconductor device socket 50b comprises a body 20a without a movablecover. In the socket 50b, the same or equivalent portions as or to thoseof Embodiment 1 are denoted by the same reference numerals. In thisembodiment, each of the movable contact terminals 30b is made of a shapememory alloy, for example, comprising a nickel-titanium (NiTi) alloy ora copper alloy (CuAlNi)(CuAuZn). At a high temperature, the movablecontact terminals 30 have a shape in which the contact terminalsrespectively contact the external leads 2 of the IC 1. Namely, the shapeat a high temperature is memorized. In FIG. 11, reference numeral 100denotes a conveyance tool for conveying the IC 1 with vacuum tweezers.Particularly, the conveyance tool 100 is provided with a cam portion 101having an arcuate surface 102 for opening each of the movable contactterminals 30 in place of the movable cover. Reference numeral 103denotes a suction head for grasping the IC 1 by suction.

The operation is described below. When the IC 1 is conveyed to aposition above the socket 50b by the conveyance tool 100, as shown inFIG. 11, each of the movable contact terminals 30 is deformed and openedby the force applied from the arcuate surface 102 of the cam portion 101of the conveyance tool 100. FIG. 11 shows the state where the IC 1 ismounted on the positioning base 21a of the body 20a in the open state.

When the socket 50b equipped with the IC 1 is placed in an environmentat a high temperature (about 80° C. to 150° C.) for the burn-in test ofthe IC 1 after the conveyance tool 100 is removed, as shown in FIG. 12,each of the movable contact terminals 30b comprising a shape memoryalloy returns to the memorized shape at a high temperature, in whicheach of the contact portions 32a contacts the shoulders 4 of thecorresponding external leads 2. In this state, the burn-in test isperformed. After the burn-in test is completed, the conveyance tool 100is moved to a position above the socket 50b, and each of the movablecontact terminals 30b is opened by the arcuate surface 102 of the camportion 101. In this state, the IC 1 is attached to the suction head 103and is separated from the socket 50b.

In this way, since each of the movable contact terminals of the socketis made of a shape memory alloy, the movable cover need not be providedon the socket, thereby simplifying the structure of the socket.

This embodiment can also be applied to the sockets the otherembodiments, and the same effects can be obtained.

This embodiment can also be applied to the conventional socket shown inFIGS. 13 and 14. When this embodiment is applied to the conventionalsocket, since the movable cover 40, for example, shown in FIG. 13 isunnecessary, the lead end supporting surface 23 of the socket body 20can easily cleaned, and the adhesion of burrs to the mounting surfaces 6of the external leads 2 of the IC 1 can be decreased.

As described above, in the semiconductor device socket in accordancewith the first embodiment, electrical contact between the external leadsof the semiconductor device and the movable contact terminals on theconnector side is achieved by the shoulders or the inclined portions ofthe external leads when the semiconductor device is mounted on thesocket, the semiconductor device is supported by the sides of theshoulders of the external leads on the rear sides thereof, and themounting surfaces at the ends of the external leads float, notcontacting the socket. This can prevent adhesion of foreign materials tothe mounting surfaces. In addition, since the end of each of theexternal leads does not make electrical connection, it is possible toprevent the lead ends from being deformed by the pressure applied duringthe test. There are thus the effects of permitting tests of thesemiconductor device with high reliability and preventing the occurrenceof defective semiconductor devices and thus increasing the yield.

In the semiconductor device socket in accordance with the secondembodiment, since the thin burrs produced when the package portion isformed remain on the shoulders of the external leads which respectivelycontact the contact potions of the movable contact terminals, thecontact portion of each of the movable contact terminals of the socketof the first embodiment is formed in a sharp shape for cutting off thethin burrs when contacting the shoulder portions, thereby producingreliable electrical contact. There is thus the effect of increasingreliability.

In the semiconductor device socket in accordance with the thirdembodiment, although the electrical connection between the externalleads and the movable contact terminals is achieved by the ends of theexternal leads, the lead end supporting surface of the socket body forsupporting the mounting surfaces of the external leads is formed in ashape or of a material, which prevents deposition and retention offoreign materials, such as irregularities in or bonding a conductivematerial for preventing the generation of static electricity to the leadend supporting surface so that the adhesion of foreign materials to themounting surfaces of the external leads can be decreased. It is thuspossible to prevent the occurrence of poor contact caused by the foreignmaterials, and the deformation of the lead ends, and thus prevent theproduction of defective semiconductor devices. There is thus the effectof increasing the yield.

In the semiconductor device socket in accordance with the fourthembodiment, movable projecting members having a smaller resilience thanthat of the movable contact terminals are provided on the lead endsupporting surface of the socket body in correspondence with therespective external leads so as to upwardly project from the lead endsupporting surface when not pressed by the contact portions of themovable contact terminals. This prevents the deposition and retention ofthe foreign materials on the movable projecting members in contact withthe mounting surfaces of the external leads, and decreases the adhesionof the foreign materials to the mounting surfaces of the external leads.It is thus possible to prevent poor contact caused by the foreignmaterials and the deformation the lead ends, perform the test with highreliability and prevent the production of defective semiconductordevices. There are thus the effects of increasing the yield andproducing a strong contact force between the external leads and themovable contact terminals.

In the semiconductor device socket in accordance with the fifthembodiment, means for positioning the IC comprises projectingpositioning guides having, for example, a conical or truncated conicalshape, and provided on the IC supporting surface of the socket body soas to make point contact with the sides of the package portion of theIC, thereby decreasing the deposition and retention of foreignmaterials, facilitating cleaning off of the foreign materials anddecreasing the adhesion of foreign materials to the mounting surfaces ofthe external leads. It is thus possible to prevent the poor contactcaused by the foreign materials and the deformation of the lead ends,perform the test with high reliability and prevent the production ofdefective semiconductor devices. There is thus the effect of increasingthe yield.

In the semiconductor device socket for testing at a differenttemperature in accordance with the sixth embodiment, each of the movablecontact terminals is made of a shape memory alloy which memorizes theshape in the state where the movable contact terminals respectivelycontact and press against the external leads, and which returns to thememorized shape at a test temperature so that the movable contactterminals automatically have a shape pressing the external leads whenplaced in an environment at the test temperature. This makes itunnecessary to provide the movable cover for opening and closing themovable contact terminals on the socket. Each of the movable contactterminals is opened by the cam portion or the like which is formed onthe conveyance tool for conveying, for example, a IC, to the socket withvacuum tweezers, the conveyance tool being provided separately from thesocket. This can further simplify the structure of the socket anddecrease the production cost of the socket. It is thus possible toeasily clean off the foreign materials on the socket and prevent poorcontact caused by the foreign materials and the deformation of the leadends.

What is claimed is:
 1. A semiconductor device socket for connecting anexternal circuit to external leads of a semiconductor device in order totest the semiconductor device, the socket comprising:a body having apositioning base for contacting and supporting shoulders of externalleads of a semiconductor device and comprising movable contact terminalsdisposed opposite to the external leads and movable into and out ofcontact with the shoulders of the external leads; and a cover mounted onthe body for movement toward and away from the semiconductor device andurging the movable contact terminals away from the external leads whenthe cover is moved toward the body.
 2. The semiconductor device socketaccording to claim 1 wherein each of the movable contact terminals has acontact portion including at least one sharp projection for scrapingburrs off the external leads.
 3. The semiconductor device socketaccording to claim 1 wherein each of the movable contact terminalsincludes a helical spring biased towards one of the external leads, thesocket including a cam for releasably urging the terminals away from theexternal leads.
 4. A semiconductor device socket for connecting anexternal circuit to external leads of a semiconductor device in order totest the semiconductor device, the socket comprising:a body forsupporting a semiconductor device and comprising a lead end supportingsurface for supporting ends of external leads of a semiconductor devicemounted on the body, the lead end supporting surface having a pluralityof spaced apart recesses separating adjacent external leads of thesemiconductor device, and movable contact terminals disposed oppositethe external leads; and a cover mounted on the body for movement towardand away from a semiconductor device mounted on the body, the coverurging the movable contact terminals away from the external leads whenthe cover is moved toward the body.
 5. The semiconductor device socketaccording to claim 4 wherein each of the external leads is supported ona portion of the lead end supporting surface that is large enough tosupport only one of the external leads.
 6. A semiconductor device socketfor connecting an external circuit to external leads of a semiconductordevice in order to test the semiconductor device, the socketcomprising:a body for supporting a semiconductor device and comprising aplurality of spaced apart electrically conductive members for supportinglead ends of external leads of the semiconductor device and a pluralityof movable contact terminals disposed opposite the external leads; and acover mounted on the body for movement towards and away from the bodyand urging the movable contact terminals away from the external leadswhen the cover is moved toward the body.
 7. A semiconductor devicesocket for connecting an external circuit to external leads of asemiconductor device in order to test the semiconductor device, thesocket comprising:a body for supporting a semiconductor device andcomprising a lead end supporting surface for supporting external leadsof a semiconductor device mounted on body, movable contact terminalsdisposed opposite to the external leads, and resilient projectingmembers insulated from the movable contact terminals and projecting fromthe lead end support surface and movable toward the lead end supportingsurface when the movable contact terminals contact the external leads;and a cover mounted on the body for movement toward and away from asemiconductor device mounted on the body, the cover urging the movablecontact terminals away from the external leads when the cover is movedtoward the body.
 8. A semiconductor device socket for connecting anexternal circuit to external leads of a semiconductor device in order totest the semiconductor device, the socket comprising:a body comprising aflat IC supporting surface for supporting the semiconductor device, aplurality of positioning pins extending upwards from the IC supportingsurface supported by the body, and movable contact terminals disposedopposite to the external leads of the semiconductor device supported bythe body; and a cover mounted on the body for movement toward and awayfrom the body, the cover urging the movable contact terminals away fromthe external leads when the cover is moved toward the body.
 9. Asemiconductor device socket for connecting an external circuit toexternal leads of a semiconductor device in order to test thesemiconductor device, the socket comprising:a body for supporting asemiconductor device and having movable contact terminals disposedopposite to external leads of a semiconductor device mounted on thebody, each of said movable contact terminals being made of a shapememory alloy that returns, at a test temperature, to a memorized shapein which each movable contact terminal is pressed against one of theexternal leads.
 10. The socket according to claim 1 wherein thepositioning base supports lower surfaces of the external leads and themovable contact terminals are movable into and out of contact with uppersurfaces of the external leads.
 11. The socket according to claim 2wherein the projections comprise serrations on the contact portion. 12.The socket according to claim 3 wherein the cam is rotated by movementof the cover toward and away from the body.
 13. The socket according toclaim 8 including a V-shaped groove in the base opposite to thesemiconductor device.
 14. The socket according to claim 13 including ahole in a bottom surface of the groove.
 15. The socket according toclaim 8 wherein the semiconductor device has four corners and one of thepositioning pins is disposed adjacent each of the corners.
 16. Asemiconductor device socket for connecting an external circuit toexternal leads of a semiconductor device in order to test thesemiconductor device, the socket comprising:a body for supporting asemiconductor device; a plurality of movable contact terminals, eachterminal being movable into and out of contact with a correspondingexternal lead of the semiconductor device and comprising a helicaltorsion spring; and a rotatable cam engaging at least one of the contactterminals for moving the contact terminal into and out of contact withthe corresponding external lead.
 17. The semiconductor device socketaccording to claim 16 including a cover movably mounted on the body formovement toward and away from the body and drivingly connected to thecam for rotating the cam to urge the contact terminal away from thecorresponding external lead when the cover is moved toward the body. 18.A semiconductor device socket for connecting an external circuit toexternal leads of a semiconductor device in order to test thesemiconductor device, the socket comprising:a body having a positioningbase for contacting and supporting shoulders of external leads of asemiconductor device and comprising movable contact terminals disposedopposite to the external leads and movable into and out of contact withinclined portions of the external leads; and a cover mounted on the bodyfor movement toward and away from the semiconductor device and urgingthe movable contact terminals away from the external leads when thecover is moved toward the body.
 19. The semiconductor device socketaccording to claim 18 wherein each of the movable contact terminals hasa contact portion including at least one sharp projection for scrapingburrs off the external leads.
 20. The semiconductor device socketaccording to claim 18 wherein each of the movable contact terminalsincludes a helical spring biased towards one of the external leads, thesocket including a cam for releasably urging the terminals away from theexternal leads.
 21. The socket according to claim 18 wherein thepositioning base supports lower surfaces of the external leads and themovable contact terminals are movable into and out of contact with uppersurfaces of the external leads.
 22. A semiconductor device socket forconnecting an external circuit to external leads of a semiconductordevice in order to test the semiconductor device, the socketcomprising:a body having a support portion for supporting asemiconductor device and having a plurality of movable contactterminals, each terminal being movable into and out of contact with acorresponding external lead of the semiconductor device, the supportportion supporting the semiconductor device such that lead ends of theexternal leads are suspended above a surface of the body adjoining thesupport portion when the movable contact terminals move into and out ofcontact with the external leads; and a cover mounted on the body formovement toward and away from the semiconductor device and urging themovable contact terminals away from the external leads when the cover ismoved toward the body and permitting the movable contact terminals tocontact the external leads when the cover is moved away from the body.